RESUMO
The pathogenesis of the muscular symptoms and recurrent rhabdomyolysis that are commonly manifested in patients with mitochondrial trifunctional protein (MTP) and long-chain 3-hydroxy-acyl-CoA dehydrogenase (LCHAD) deficiencies is still unknown. In this study we investigated the effects of the major long-chain monocarboxylic 3-hydroxylated fatty acids (LCHFA) accumulating in these disorders, namely 3-hydroxytetradecanoic (3HTA) and 3-hydroxypalmitic (3HPA) acids, on important mitochondrial functions in rat skeletal muscle mitochondria. 3HTA and 3HPA markedly increased resting (state 4) and decreased ADP-stimulated (state 3) and CCCP-stimulated (uncoupled) respiration. 3HPA provoked similar effects in permeabilized skeletal muscle fibers, validating the results obtained in purified mitochondria. Furthermore, 3HTA and 3HPA markedly diminished mitochondrial membrane potential, NAD(P)H content and Ca(2+) retention capacity in Ca(2+)-loaded mitochondria. Mitochondrial permeability transition (mPT) induction probably underlie these effects since they were totally prevented by cyclosporin A and ADP. In contrast, the dicarboxylic analogue of 3HTA did not alter the tested parameters. Our data strongly indicate that 3HTA and 3HPA behave as metabolic inhibitors, uncouplers of oxidative phosphorylation and mPT inducers in skeletal muscle. It is proposed that these pathomechanisms disrupting mitochondrial homeostasis may be involved in the muscle alterations characteristic of MTP and LCHAD deficiencies.
Assuntos
Cardiomiopatias/metabolismo , Erros Inatos do Metabolismo Lipídico/metabolismo , Mitocôndrias Musculares/efeitos dos fármacos , Miopatias Mitocondriais/metabolismo , Proteína Mitocondrial Trifuncional/deficiência , Ácidos Mirísticos/farmacologia , Doenças do Sistema Nervoso/metabolismo , Ácidos Palmíticos/farmacologia , Rabdomiólise/metabolismo , Animais , Cálcio/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/fisiologia , Proteína Mitocondrial Trifuncional/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , NADP/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Ratos WistarRESUMO
Mitochondrial trifunctional protein and long-chain 3-hydroxyacyl-CoA dehydrogenase deficiencies are fatty acid oxidation disorders biochemically characterized by tissue accumulation of long-chain fatty acids and derivatives, including the monocarboxylic long-chain 3-hydroxy fatty acids (LCHFAs) 3-hydroxytetradecanoic acid (3HTA) and 3-hydroxypalmitic acid (3HPA). Patients commonly present severe cardiomyopathy for which the pathogenesis is still poorly established. We investigated the effects of 3HTA and 3HPA, the major metabolites accumulating in these disorders, on important parameters of mitochondrial homeostasis in Ca(2+) -loaded heart mitochondria. 3HTA and 3HPA significantly decreased mitochondrial membrane potential, the matrix NAD(P)H pool and Ca(2+) retention capacity, and also induced mitochondrial swelling. These fatty acids also provoked a marked decrease of ATP production reflecting severe energy dysfunction. Furthermore, 3HTA-induced mitochondrial alterations were completely prevented by the classical mitochondrial permeability transition (mPT) inhibitors cyclosporin A and ADP, as well as by ruthenium red, a Ca(2+) uptake blocker, indicating that LCHFAs induced Ca(2+)-dependent mPT pore opening. Milder effects only achieved at higher doses of LCHFAs were observed in brain mitochondria, implying a higher vulnerability of heart to these fatty acids. By contrast, 3HTA and docosanoic acids did not change mitochondrial homeostasis, indicating selective effects for monocarboxylic LCHFAs. The present data indicate that the major LCHFAs accumulating in mitochondrial trifunctional protein and long-chain 3-hydroxyacyl-CoA dehydrogenase deficiencies induce mPT pore opening, compromising Ca(2+) homeostasis and oxidative phosphorylation more intensely in the heart. It is proposed that these pathomechanisms may contribute at least in part to the severe cardiac alterations characteristic of patients affected by these diseases.
Assuntos
Sinalização do Cálcio , 3-Hidroxiacil-CoA Desidrogenase de Cadeia Longa/metabolismo , Mitocôndrias Cardíacas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Ácidos Mirísticos/metabolismo , Fosforilação Oxidativa , Ácidos Palmíticos/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Cardiomiopatias/enzimologia , Cardiomiopatias/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Erros Inatos do Metabolismo Lipídico/enzimologia , Erros Inatos do Metabolismo Lipídico/metabolismo , 3-Hidroxiacil-CoA Desidrogenase de Cadeia Longa/deficiência , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/enzimologia , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Miopatias Mitocondriais/enzimologia , Miopatias Mitocondriais/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Dilatação Mitocondrial/efeitos dos fármacos , Proteína Mitocondrial Trifuncional/deficiência , Proteína Mitocondrial Trifuncional/metabolismo , NADP/metabolismo , Doenças do Sistema Nervoso/enzimologia , Doenças do Sistema Nervoso/metabolismo , Especificidade de Órgãos , Fosforilação Oxidativa/efeitos dos fármacos , Ratos Wistar , Rabdomiólise/enzimologia , Rabdomiólise/metabolismoRESUMO
Patients with long-chain 3-hydroxy-acyl-CoA dehydrogenase (LCHAD) deficiency commonly present liver dysfunction whose pathogenesis is unknown. We studied the effects of long-chain 3-hydroxylated fatty acids (LCHFA) that accumulate in LCHAD deficiency on liver bioenergetics using mitochondrial preparations from young rats. We provide strong evidence that 3-hydroxytetradecanoic (3HTA) and 3-hydroxypalmitic (3HPA) acids, the monocarboxylic acids that are found at the highest tissue concentrations in this disorder, act as metabolic inhibitors and uncouplers of oxidative phosphorylation. These conclusions are based on the findings that these fatty acids decreased ADP-stimulated (state 3) and uncoupled respiration, mitochondrial membrane potential and NAD(P)H content, and, in contrast, increased resting (state 4) respiration. We also verified that 3HTA and 3HPA markedly reduced Ca2+ retention capacity and induced swelling in Ca2+-loaded mitochondria. These effects were mediated by mitochondrial permeability transition (MPT) induction since they were totally prevented by the classical MPT inhibitors cyclosporin A and ADP, as well as by ruthenium red, a Ca2+ uptake blocker. Taken together, our data demonstrate that the major monocarboxylic LCHFA accumulating in LCHAD deficiency disrupt energy mitochondrial homeostasis in the liver. It is proposed that this pathomechanism may explain at least in part the hepatic alterations characteristic of the affected patients.
Assuntos
3-Hidroxiacil-CoA Desidrogenases/deficiência , Cardiomiopatias/patologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/farmacologia , Erros Inatos do Metabolismo Lipídico/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Miopatias Mitocondriais/patologia , Dilatação Mitocondrial/efeitos dos fármacos , Doenças do Sistema Nervoso/patologia , Rabdomiólise/patologia , 3-Hidroxiacil-CoA Desidrogenases/metabolismo , Animais , Transporte Biológico , Cálcio/metabolismo , Cardiomiopatias/metabolismo , Erros Inatos do Metabolismo Lipídico/metabolismo , Mitocôndrias Hepáticas/metabolismo , Membranas Mitocondriais/metabolismo , Miopatias Mitocondriais/metabolismo , Proteína Mitocondrial Trifuncional/deficiência , NADP/metabolismo , Doenças do Sistema Nervoso/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Ratos , Ratos Wistar , Rabdomiólise/metabolismoRESUMO
The TNF-α serum level increases after rhabdomyolysis and is involved in the subsequent cardiorenal injury. In the present study, we investigated the TNF-α-dependent cell signaling pathways implicated in cellular injury in these organs. Rhabdomyolysis was induced by intramuscular glycerol injection in rats. Renal function, cardiac and renal pathology, and activation of caspases were evaluated during the first 24 h after glycerol injection. TNF-α blockade with infliximab reduced tubular necrosis and cardiorenal apoptosis. Cellular Fas-associated protein with death domain-like IL-1ß-converting enzyme inhibitory protein (cFLIP), an inhibitor of caspase-8, was overexpressed in the kidney but not in the heart. The inhibitory effect of cFLIP blunted caspase-8 activation in the kidney. In this condition, the cellular response to the TNF-α stimulus was driven to receptor-interacting protein-1 (RIP1)-mediated necroptosis. Treatment with RIP1 inhibitor (necrostatin-1) isolated or in combination with infliximab showed a similar reduction in tubular necrosis, underscoring the importance of TNF-α-mediated tubular necroptosis in this model. TNF-α played a positive regulatory role in the transcription of proapoptotic Bax and p53-upregulated modulator of apoptosis (PUMA) proteins. Infliximab treatment reduced caspase-9-mediated apoptosis in both organs. Treatment with a caspase-8 inhibitor showed that caspase-8 participated in the process of apoptosis only in the heart, upstream of caspase-9 activation. TNF-α-mediated necroptosis is the predominant form of tubular injury observed in the glycerol model. TNF-α up regulates Bax and PUMA proapoptotic proteins, resulting in activation of the intrinsic pathway of apoptosis in the kidney and heart.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Apoptose/efeitos dos fármacos , Inibidores de Caspase/farmacologia , Rabdomiólise/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose/fisiologia , Caspase 8/metabolismo , Caspase 9/metabolismo , Modelos Animais de Doenças , Masculino , Necrose/metabolismo , Ratos Wistar , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Transdução de Sinais/fisiologia , Proteína Supressora de Tumor p53/metabolismoRESUMO
We report 2 cases of fatal rhabdomyolysis in children carrying an LPIN1 mutations preceded by similar electrocardiogram changes, including diffuse symmetrical high-amplitude T waves. Our report underlines the severity of this disease and the need for active management of episodes of rhabdomyolysis in a pediatric intensive care unit.
Assuntos
DNA/genética , Predisposição Genética para Doença , Mutação , Fosfatidato Fosfatase/genética , Rabdomiólise/genética , Biópsia , Criança , Pré-Escolar , Análise Mutacional de DNA , Diagnóstico Diferencial , Evolução Fatal , Feminino , Seguimentos , Humanos , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteínas Nucleares , Fosfatidato Fosfatase/metabolismo , Rabdomiólise/diagnóstico , Rabdomiólise/metabolismoRESUMO
La ocurrencia de un episodio de rabdomiolisis (RML), de esfuerzo en individuos que hacen regularmente actividad física sin limitaciones es poco frecuente y puede ser la primera manifestación de una miopatía metabólica o mitocondrial. Objetivo: Estudiar si dos sujetos que sufrieron un episodio de RML de esfuerzo tienen un comportamiento distinto a sujetos controles durante una prueba de ejercicio máximo (PEM) en un laboratorio de función cardiopulmonar y si después del esfuerzo presentan evidencias bioquímicas de sufrimiento muscular o renal. Sujetos y métodos: Se empleó un cicloergómetro incrementando la carga en 30 watts cada dos minutos, hasta que los sujetos decidieran que eran incapaces de continuar el ejercicio. Se usó un neumotacógrafo para medir el consumo de O2 y producción de CO2 y se monitorizaron la frecuencia respiratoria, electrocardiograma, presión arterial y oximetría de pulso. Se hicieron determinaciones bioquímicas antes, durante y hasta 24 horas de terminada la PEM. Resultados: Los sujetos y sus controles toleraron una carga de hasta 220-240 watts, el comportamiento fisiológico frente al ejercicio fue similar y no hubo evidencias de daño renal o muscular. Conclusiones: El comportamiento frente a la PEM descartó razonablemente que los dos sujetos que hicieron una RML tuvieran una alteración del metabolismo muscular por lo que se les autorizó a reiniciar su actividad física habitual.
Assuntos
Humanos , Masculino , Adulto , Rabdomiólise/metabolismo , Tolerância ao Exercício/fisiologia , Estudos de Casos e Controles , ChileRESUMO
A rabdomiólise é incomum, mas é o efeito adverso mais sério observado na terapia hipolipemiante com estatinas. A ocorrência de rabdomiólise fatal reportada nos Estados Unidos desde a introdução das estatinas no mercado, na década de 1980, foi muito rara (0,15 casos por milhão de pacientes tratados por ano). Entretanto, a miopatia, definida como: sintomas musculares associados com elevações da CK; é muito mais comum (1 por cento-5 por cento). Os mecanismos de miopatia mediada por estatinas não estão totalmente compreendidos. Várias hipóteses têm sido propostas: diminuição dos níveis celulares de isoprenóides e ubiquinona, incremento de apoptose, mudanças nos canais de cloro diminuindo a hiperpolarização da membrana celular e alterações da permeabilidade da membrana celular. Interação com outras drogas, e alterações metabólicas pré-existentes podem predispor a miopatia.
Assuntos
Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Rabdomiólise/induzido quimicamente , Apoptose/efeitos dos fármacos , Ciclosporina/efeitos adversos , Ciclosporina/metabolismo , Creatina Quinase/análise , Interações Medicamentosas , Doenças Cardiovasculares/prevenção & controle , Inibidores de Hidroximetilglutaril-CoA Redutases/metabolismo , Rabdomiólise/metabolismoRESUMO
Rhabdomyolysis is uncommon, but is a serious side-effect observed following statin use. The occurrence of fatal rhabdomyolysis reported in the USA since the introduction of statins in the market in the late eighties was very rare (0.15 cases per million patients treated per year). However, myopathy, defined as muscle symptoms associated with CK elevation is much more common (1-5%). Mechanism of statin-induced myopathy is not fully understood. Several hypotheses have been proposed: decreased cellular levels of isoprenoids and ubiquinone, increased rates of apoptosis, changes in chloride channels impairing cell-membrane hyperpolarization, and changes in the cell-membrane permeability. Interactions with other drugs, and preexisting metabolic alterations may predispose to myopathy.